You may get an error While installing and configuring X264 in FFMPEG, we have already discussed about FFMPEG  installation , FFMPEG-PHP and some errors fixes on previous posts.
 

# ./configure --enable-gpl --enable-libx264


  Found yasm 1.x.x.xxxx

  Minimum version is yasm-1.0.0

  If you really want to compile without asm, configure with --disable-asm.


   that means that you have installed old version of yasm, so you need to update latest one with following commands,
  
 # cd /usr/local/src

  # git clone git://github.com/yasm/yasm.git

  # cd yasm

  # ./autogen.sh

  # ./configure 

  # make

​  # make install